Cellulose solutions and process for their production



Patented July 29, 1930 LEON LILIENIELD, or VIENNA, aus'r'nm cnLLnLosE SOLUTIONS mnraocnss non r'n'nm raonuc'rronf m5 Drawing. Application filed May 10, 1924, Serial No. 712,475, and in Austria June 5, 1928.

ticularly quaternary ammonium bases or those bases in the aqueous solutions of which a highly electrolytic dissociated hydroxide is assumed -to be present, have a dissolving effect on cellulose or its conversion products, is not only surprising in itself. It must be described as entirely unexpected, that the I solvent action of these bases even exceeds that of caustic alkalies, so far as such action exists. The more powerful solvent actlon of the strong organic bases is evident from the.

fact, for example, that whereas caustic alkali lyes are able to dissolve mercerized cellulose or bleached cellulose or bleached and mercerize'd cellulose or'certain cellulose conversion products obtained from cellulose solutions, such as the cellulose hydrate regenerated from viscose, including viscose silk, or the cellulose conversion product obtainable from ammoniacal solutions of cupr1c oxide by precipitation, including copper silk and the like, only at low temperatures, such bodies from the cellulose group are d1ssolved even at room temperature 1n aqueous solutions of strong organic bases, for example a solution of 20-50 percent. strengthof tetra-ethylammoniumhydroxide or tetramethylammoniumhydroxide or phenyltrimethylammoniumhydroxide or guanidine. Thus, according to the particular nature of the body from the cellulose group to be dissolved, the solvent action of the strong organic bases or of their aqueous solutions, in presence or absence of alkalies, takes effect either at room temperature or at ahlgher dissolves either at room temperature or be 'far below 0, whereas slightly disintegrated temperature or at a .temperature between room temperature and 0, or only below 0".

Thus, for exam le, those conversion products which may e obtained by separation from solutions of cellulose in suitable solvents (for example strong mineral acid, ammaniacal cupric oxide, zinc chloride) or from viscose, dissolve in suitable bases or aqueous solutions thereof in presence or absence of alkali even at room temperature. Mercerized cellulose or bleached cellulose or bleached and mercerized cellulose, according to the degree of mercerizing or bleaching,

tween room temperature and 0 or not very or not disintegrated cellulose dissolves only below 0 in the bases or aqueous solutions thereof in presence or absence of alkalies. In every case it is easy to determine the proper temperature by a simple preliminary test, namely by mixing the cellulosic body with the desired base or solution thereof in Water alone or in presence of alkali and, if no solution occurs at room temperature, cool-,- ing by sta es until a solution is produced.

Hereina ter the conduct of the process is described and illustrated by examples. It

is, however, expressly emphasized that it is not intended to limit the invention to the details of this descri tion.

.As parent materia s for the present process the following may be named by way of example:

(1) Bleached or unbleached cellulose of every kind and in every form in which it is available; i 1 (2) Every kind of matter containing cellu- (3) Ihose conversion products which are formed by mechanical comminution (for example grinding or shredding) of the cellulose in presence ofwater;

(4) Cellulose conversion products or oxidation products obtained by treating cellulose or its conversion products with oxidizing or reducing bleaching agents of every kind, 1 irrespective of whether a preliminary treat ment (for example with alkalies, acids, salts we or the like) has or has not preceded the bleaching operation;

made by treating cellulose or its conversionproducts with alkali lye of various concentrations and, where necessary, removingthe .excess alkali lye by pressing, centrifuging or the like (mercerizing the cellulose), with-or without subsequent washing,-with or without subsequent treatment with a dilute acid I and with or without previous or subsequent or simultaneous treatment with bleachmg or oxidizing agents;

(7) Those cellulose conversion products obtained by treatingcellulose with hot alkalies in presence or absence of salts;

(8) The cellulose conversion products which are separated from complete or incomplete solutions of cellulose or of its conversion products by suitable precipitating agents or other means and, if desired, purified by washing; for example from solutions or pastes of cellulose or cellulose hydrates or hydrocelluloses in ammoniacal cupric oxide or in any other solvent containing copper as a basis, or

. from solutions or pastespf cellulose or celluloseh drates or hydro-celluloses in zinc halides, or example zinc chloride alone or in Ichloric acid, arsenic aci presence of an acid or a salt, or from solutions or astes of cellulose or cellulose hydrates or hydrocelluloses in strong mineral acids, such as sulphuric acid, phos horic acid hydroand the like alone or mixed with each other or in admixture with other inorganic or organic acids or acid salts, or from crude or purified viscoses (cellulose xanthates) when decomposed spon taneously or by other means.

' cellulose conversion products separated from solvents, such as strong mineral aci s (for' example parchinentizing acid) orzinc halides (forexample zinc chloride or the like) or ammoniacal cupric oxide;

(10) Hydro-celluloses of every kind,- ;such

as' are obtained, for example, by treating bleached or unbleached cellulose -'with dilute acids in the cold or at a raised temperature under ordinary or increased pressure or by drying in presence of acids or by 'treating cellulose with strong sulphuric acid of specific gravity lower than 50 Baum in thecold,

gaseous hydrochloric acid or chlorine;

(11) Oxy-celluloses of every kind.

Of all the ,The aforesaid conversion or oxidation products may be used in the dry, air-dry,

moist or wet state. In the last two cases the percentage of water in the parent material must be taken into account when determining the strength and proportion of the solution of the base intended for the dissolution.

In the succeeding portion of the description and in the claims, wheresoever the meaning admits, the term cellulose is intended to include cellulose, and its conversion products such as cellulose hydrate, hydrocellulose and oxycellulose.

The conduct of the process is simple. It consists substantially in treating the cellulose with a preferably aqueous solution of a strong organic base, for example a quaternary ammonium base or a base in the aqueous solution of which a highly electrolytically dissociated hydroxide is assumed to be present or two or more such bases, in presence or absence of caustic alkali, preferably while stirring, at a temperature suitable for dissolving the cellulosic body concerned, until dissolution occurs. Instead of the base itself, there may be used mixtures of such substances as are capable of forming the base in questioner substances capable of conversion, with formation of the base in question.

If dissolution is effected while cooling, it is conducted preferably in a vessel adapted to be cooled either externally or internally or both externally and internally and having in addition a mixing, kneading or stirring device. Y

The solutions of the bodies obtained according to the present process, if desired after previous filtering or straining or centrifuging may be used for making technical products such as artificial threads or yarns (for example artificial silk, artificial cotton, staple fibre or the like), artificial hair, films of every kind, plastic masses, coatings of every kind upon paper, textiles, leather and the like, finishings and fillings for fabrics, sizing for %:{IJ;IIIS, book cloth, artificial leather and the The solutions are easily worked up' into technical products,'since they are readily coagulated by suitable precipitating baths, v

such as inorganic or organic acids, salts, alcohols, in some cases even water, or by heat, steam and the like.

The following examples illustrate the invention, the parts being by weight parent materials:

(1) Finely subdivided sulphite-cellulose;

1 ample in the following manner:

100 parts of sulphite-cellulose in fleece or sheet form or medicated cotton wool are impregnated with 900 tolOOO parts of a caustic I soda lye of 18 tof30 per cent. strength of room temperature; the mass is left in the caustic soda lye for 6 up to 24 hours and then immediately washed or is first pressed or centrifuged until it weighs 200 to 300 parts an shaken or comminuted in a suitable apparatus (for example shredder, beater, willowing ma-' chine or the like) and, either directly after comminution or after standing for 1 up to?) days at room temperature, washed with cold or hot water. The washed, mercerized cellulose is' then pressed'or centrifuged and dried in a vacuum or in the air or used in the centrifuged or pressed state, where desirable after previous comminution.

(4;) Cellulose comminuted or ground in presence of water and produced, for example,

in the, following manner 200' parts of sulphite-cellulose in fleece or sheet form are stirred with 10 to 20 times their weight of water until the mixture is homogeneous, and after standing for several hours or. several days at room temperature it is pressed or centrifuged until it weighs 250 to 350 parts. The residue is ground or comminuted for several hours up to 8 days in a suitable apparatus (for example shredder, beater, willowing machine, kneading machine or the like) and, if desired, dried.

(5) Cellulose previouslytreated with dilute mineral acids, for example according to the following directions a 100 parts of bleached or unbleached sulphit-e-celluloseare boiled with 1000 to i000 parts of hydrochloric acid of A percent. strength in an open vessel for up to 3 hours, then, if desired, after previous pressing or centrifuging, the product is washed anddpressed or centrifuged and, if desired, dri'e a (g) Viscose silk-or copper silk or waste of suc silks. v (7) Cellulose hydrate obtained by precipitating or treating viscose in the dissolved or undissolved state that is to sa sul hidized alkali cellulose be ore its disso ution wi th a dilute mineral acid, for examle sulphuric acid of 5 per cent. strength, was ing' the precipitate and, if desired, drying.

(8) Cellulose conversion products obtained by dissolving cellulose 1n strong sulphuric acid and precipitating with water or dilute acids,'for example according to the following directions v Into 1000 to 2000 parts of sulphuric acid of Baum specific gravity, cooled to 12 C.', '100 parts of finely subdivided sulphite-cellulose are introduced in small homogeneous.

portions while kneadin or mixin' and continuousl cooling. he intr uction occupies a out 20 minutes. The temperature of the mass is kept at about 10 to 11 'C. during the introduction. After the whole of the sulphite-cellulose is incorporated in the sul huric acid, the product is a tough dough w llCll may be rolled out on a glass plate and, in a thin layer, appears transparent. This dough, is continuousl cooled to -10 C. to --12 C., while knea 'ng for another to 1 hour, and is then kneaded with ice water, added in small portions, until is is entirely broken up. The

.product (if desired after previous pressmg for the purpose. of recovering the sulphuric acid is washed with water until sulphuric acid can no lon er be detected in the washing water and unti a test portion of the body itself, boiled with water, ields nov more sulphuric acid to the water. 0 ac celera'te the washing operation, the more or less coarse product may be triturated or ground in the moist state once or several times during the washing. The washed body is now pressed or. centrifu ed, if necessary again triturated or ground and used either in the wet state or'after having been dried in a vacuum or in the air.

Whichever of the foregoing parent materials is used it is mixed with an aqueous soluof 20 to 50 per cent. strength, whereupon the 7 mass is stirred at room temperature until it is The result in the case of parent material it, 2, 3 and 4 is merely a more or less appreciable swelling, whereas in the case of parent materials 5, 6, 7 and 8 dissolution ocours to a considerable extent.

Then, preferably while stirring or knead-' ing, the mass is cooled to--8 to 11 C. and kept at this temperature for some seeonds up to 30 minutes.

Under the action of the cold dissolution occurs m the first four cases; in the last four improvement, that is to say completion of,

the solution alread begun. The solutions are viscous, but liquid, and may be freed from any undissolved constituents that may be present straining, filtering or centrifuging. Sprea in thin layers on glass plates and treated with a suitable precipitating bath (for example dilute sulphuric acid), these solutions. yield films which are transparent and flexible after washing and drying. They mavalso be worked up into artificial threads, such as artificial 'silk,.by spinning into suitable precipitating baths (for example dilute the result is roughly as in Example I.

III

10-15 parts of dicyano-diamide, preferably pulverized, are stirred with 200-240 parts of sodium hydroxide solution of 6 er cent strength, whereupon 10 parts of airry cellulose mercerized by sodium hydroxide are introduced and the whole is stirred until homogeneous. The mass is cooled to 10 to 11 (3., while stirring, and is kept at this temperature while stirring for 10-40 minutes,

during which the mass freezes but can still be stirred. After thawing there is produced. a liquid solution which yields a film clear and firm while wet and transparent, and flexible I when dry.

I claim: 1. Process for making cellulose solutions by dissolving cellulose in guanidine.

2. Process for making cellulose solutions by dissolving cellulose in guanidine at a temperature below 0 C.

3. Process for making cellulose solutions by dissolving cellulose in an aqueous. liquid containing guanidine. v

4. Process for making cellulose solutions by dissolving cellulose in an aqueous liquid containing guanidine' at a temperature below 0 C.

- 5. Process for-making cellulose. solutions 1 by dissolving cellulose in an aqueous liquid containing guanidine andjcausticalkalig containing guanidine and caustic alkali-.at'a temperature below 0 C. j 7. Process for making cellulose solutions by dissolvinga cellulose conversion product in an aqueous liquid containing guanidine.-

8. Process for making cellulose solutions by dissolving a cellulose conversion product in an aqueous liquid containing guamdine at a temperature below 0 C.

9. Process for making cellulose solutions by dissolving a cellulose conversion product in an aqueous liquid containing guanidine and caustic alkali.

10. Process for making cellulose solutions by dissolving a cellulose. conversion product off.

6. Process for making cellulose solutions. by dissolving cellulose in an aqueous liquid tives in an aqueous liquid containing guanidine and caustic alkali at a temperature below 0 C.

11. As a new-product, a solution of cellulose in'a solvent comprising water and guani dine. 12. As'a new product, a solution of cellulose in a solvent comprising water, caustic alkali and guanidine.

13. The process for making cellulose solutions which com rises dissolving cellulose in a compound of t e type R1 HN=C where R and R are NH groups or derivatives thereof.

14. The process for making a cellulosic solution which com rises dissolving a cellulose conversion pro uct in a compound of the type where R and R are NH groups or derivatives thereof.

15. The process for making a cellulosic solution which comprises dissolving cellulose in an aqueous liquid in the presence of a compound of the type. a

tives thereof.

16. The rocess for making a cellulosic solution which comprises dissolving cellulose in an a ueous li uid in the presence of a h droxi eofan al alimetal andacompound o the type l Rl hereof.

' .1+, M1 0 In I r i m "T:

groups or deriva:

R aqd R', are 'NH,-groups or derivawhere R; and R are NH: groups or deriva- I 18'. The process for makin a. cellulosic I solution which comprises disso ving cellulose atatemperature below 0 C. in an aqueous llqllld 1n the presence of a compound of. the type B1 HN=C where R and R are NH groups or derivatives thereof.

19. The process for making a cellulosic I solution which comprises dissolving cellulose at a temperature below 0 C. in an aqueous izs li uid in the, presence of a. hydroxide of an I a ali metal and a compound of the type Bl rm=o RI where R and R, are NH, groups or derivatives thereof.

20. As a new product, a' solution of cellulose in a compound of the type M jnN=o R: r where R and R, are NH, groups or derivatives thereof. I

21. Ass. new product, a solution of cellu- M lose in an aqueous liquid containing u, com

pound of the type where R and R, are NIL groups or derivatives thereof.

'22. As a. new product, a solution of cellulose in guanidine. v

23. In the process of treating cellulose, cellulose' hydrate, hydrocellulose or oxycellu-- lose, for the purpose of-swelling the same or forming solutions thereof, the stepjwhich comprises treating the same with a comab pound of the type Bl HNIC R: where R and R are NH, groups or derivatives thereof, the said treatment being conducted under such conditions of temperature as to produce swelling or dissolving as desired.

In testimon whereof I aflix my si ature.

40 R. LEON LILIEN LD. 

